I did wonder about the funnel or cheesecloth, as near the start, the niece was present near the cradle but not the bottle, and the nicotine could have been soaked onto with if they were on that tray; but that would not explain the need to switch bottles later, so can't be correct.

Either, the was opened, poison added, and re-corked by the niece with huge biceps and a recorking machine in the corner of the cellar, or the butler did it. Or both. The butler IS the niece, with a false moustache?

Well well. Who could have expected that we'd arrive here so soon - only a page and a half remains and it makes no sense to leave half the final exposition until tomorrow so here you are, the end of the road and a dose and a half of goodness. Enjoy it. It's been fun. Soyez soin. A bientôt.

The butler did it? Dotty Sayers does it again, I was fooled by the assumption that poison was traditionally a female murder weapon. Most enjoyable Daniel. And congratulations on finding a story with port at it's heart.

Great entertainment Daniel...thank you. All that is needed now is a nice glass of Dow 1908 to mark the end of this wonderful serial.

For those interested in other Maxims from 'The Salesman's Handbook' that Egg seems to live by, I found the below collection...

-To serve the public is the aim of every salesman worth the name
-It's useless to bluster and say "No, no", when it's perfectly clear that the facts are so
-Don't let the smallest chance slip by; you never know until you try
-If you're a salesman worth the name at all, you can sell razors to a billiard ball
-The hardest problem's easy of solution when each one makes his little contribution
-Whether you're wrong or whether you're right, it's always better to be polite
-Ready to learn means ready to earn
-The haberdasher gets the golfer's trade by talking, not of buttons, but of Braid
-Account with rigid honesty for £ and s and even d
-The goodwill of the maid is nine-tenths of the trade
-Don't trust to luck but be exact, and certify the smallest fact
-The salesman with the open eye sees commissions mount up high
-Don't wait for unpleasant disclosures to burst. If the truth must be told, see you tell it first
-The salesman who will use his brains will spare himself a world of pains
-Well-kept hands that please the sight, seize the trade and hold it tight, but bitten nails and grubby claws well may give the buyer pause
-Discretion plays a major part in making up the salesman's art
-The salesman's job is to get the trade - don't leave the house till the deal is made (Monty's motto)
-Attend to details and you'll make your sale - a little weight will often turn the scale
-Never miss a chance of learning for that word spells "£" plus "earning"
-When it's a question of stamps to lick, the office-boy knows most of the trick
-If accidents happen and you are to blame, takes steps to avoid repetition of same

A butler of good standing would be very deferential to those he thought of as his superiors but quite dismissive and authoritarian over those beneath him. A salesman visiting the master's house would fall into the latter category, as evidenced by the greeting on the previous occasion.

On this particular day Craven would be feeling guilty and perhaps behaving out of character, thus addressing the salesman in an unusual manner.